Acid-dyeable fibers of polyester modified with a tetramethylpiperidine compound having two ester-forming groups

ABSTRACT

Textile fibers or filaments prepared from polyesters modified with a minor proportion of a 2,2,6,6-tetramethylpiperidine compound to provide dyeability with acid dyes. The tetramethylpiperidine compounds used to modify the polyester have two ester-forming groups and can be mixed wtih polyesters, or polyester-forming compositions, at elevated temperatures to react and copolymerize into polyester molecules without limiting molecular weight as in the case of monofunctional modifiers. Polyesters modified with a variety of difunctional tetramethylpiperidine compounds are illustrated.

United States Patent [1 1 Tanikella Aug. 26, 1975 ACID-DYEABLE FIBERS OF POLYESTER MODIFIED WITH A TETRAMETHYLPIPERIDINE COMPOUND HAVING TWO ESTER-FORMING GROUPS [75] Inventor: Murty S. Tanikella, Newark, Del.

[73] Assignee: E. I. Du Pont de Nemours and Company, Wilmington, Del.

[22] Filed: Sept. 13, 1974 [2]] Appl. No.: 505,954

Related US. Application Data [63] Continuation-in-part of Ser. No. 4l9,440, Nov. 27,

I973, abandoned, and a continuation-in-part of Ser. No. 403,324, Oct. 3, I973, abandoned, each is a continuation-in-part of Ser, No. 290,771, Sept. 20, 1972, abandoned.

[30] Foreign Application Priority Data Sept. 17, 1973 Germany 2346734 [52] US. Cl. 260/76; 260/47 CZ; 260/75 N; 260/77 [51] Int. Cl. C08G 63/68 [58] Field of Search 260/75 N, 76, 77

[56] References Cited UNITED STATES PATENTS 2,647,104 7/1953 Shivers v. 260/75 Munakata et al.....,...,. 260/926 Matsui et al. 260/45.8

FOREIGN PATENTS OR APPLICATIONS 7,013,976 3/1971 Netherlands 2,043,748 3/1971 Germany 2.204.659 8/1972 Germany 32,434 8/]972 Japan OTHER PUBLICATIONS Lutz et al., J. Org. Chem., 27, 1965-1703 ([962).

Primary ExaminerMelvin Goldstein [57] ABSTRACT 16 Claims, No Drawings ACID-DYEABLE FIBERS OF POLYESTER MODIFIED 'ITH A TE'I'RAMETHYLIII'ERIDINI'I COMPOUND HAVING TWO ESTER-FORMING GROUPS REFERENCE TO PREVIOUS APPLICATIONS This is a continuation-in-part of my copending (and now abandoned) applications Ser. No. 4l).-l40 filed Nov. 27. 1973. and Ser. No. 403.324 filed Oct. 3. 1973, as continuations-in-part ofSer. No. 290.77 1 filed Sept. 20. I972 (now abandoned).

BACKGROUND OF THI' INVENTION This invention relates to textile fibers and filaments of linear glycol-terephthalate copolyesters. and is more particularly concerned with products of copolyesters having basic nitrogencontaining groups to provide improved dyeability with acid dyes.

Although many methods have been tried for improving the acid-dyeability of polyester fibers and filaments by incorporating nitrogen-containing modifiers in polyesters. such previous attempts have not provided adequate solutions to the problem for various reasons. In order to provide good dyeability with acid dyes. the modifier should contain a highly basic nitrogen atom which is suitably positioned as a dye site but which does not form a reactive center for polymer degradation reactions. That is. the modifier should be compatible with the polyester and should not result in objectionable discoloration or inadequate molecular weight The modifier should have sufficient thermal stability for incorporation in the polyester during condensation polymerization and for melt-spinning into filaments. The amount of modifier required for good dyeability should not be so great as to dilute desirable physical properties of the polyester. The modifier should have low volatility to prevent escape with low-boiling compounds re moved during the condensation polymerization and should not limit the molecular weight of the aciddyeable polyester. The melt-spun filaments should retain a high level of dyeability when subjected to heatsetting treatment after drawing. The dyed filaments and fibers should have good dye-lightfastness and resistance to washing or dry cleaning.

SUMMARY OF THE INVENTION The present invention provides improvements in the above respects in acid-dyeable textile fibers and filaments of linear glycol-terephthalate copolyester molecules containing basic nitrogen atoms. In accordance with this invention. the fibers or filaments are composed of a linear glycol-tcrephthalate copolyestcr with a minor proportion. sufficicnt to provide at least 0.02 weight percent nitrogen. of a 2.2.(mb-tetramethylpiperidine compound having substituents at the 1 and/or 4 However. any of the glycol-terephthalate polyesters useful in textile fibers can be modified in accordance with this invention to impart good aciddyeability.

Preferably an amount of modifier is used which proides 0.02 to 0.25 weight percent basic nitrogen. based on the weight of the polyester. The 2.2.6.6-tetramethylpiperidine compound preferably has substituents at the l and 4 positions of the tetramethylpiperidine ring and each substituent comprises an ester-forming group.

DETAILED DESCRIPTION The acid-dyeable polyester fibers and filaments of this invention are characterized by the presence of Z.2.6.b-tetramethylpiperidine groups in at least some of the polyester molecules. These acid-dycable polyesters are surprisingly free from undesirable discoloration. This unexpected achievement is believed to be due. at least in part. to the high hasicity of the piperidine nitrogen atom. which leads to strong dye-polymer interactions. and to the presence of the 2.2.6.6-tetramethyl substituents on the piperidine ring which hinder the approach of reactive centers which cause polymer degradation. for example. discoloration and quaternization reactions. to occur. In addition. the difunctional tetramcthylpiperidine compounds used to modify polyesters in the practice of this invention are readily copolymerized into polyester molecules and thus their use does not limit molecular weight as does the use of monofunctional modifiers.

The acid dye-ability of the polyester composition is dependent on other factors in addition to the base strength of the amine used in its preparation. In general. polyester compositions prepared with a given tetramethylpiperidinc compound will have increasing dy'eahility with increasing nitrogen content. with increasing hydrophilic character at constant nitrogen content. and with increasing content of a conventional copolymerizable compound. The acid-dyeable fibers and filaments of this invention that can be acid dyed at a pH of 3.5 and above are preferred embodiments and those that can be dyed at a pH of 4.5 and above are cspccially preferred. Of course. lower pH values. e.g.. 3.0. can be used when desired.

The tetramethy'lpiperidine modifier compounds used in this invention must exhibit good thermal stability. since polyester preparation and melt-spinning are carried out at elevated temperatures. e.g.. temperatures within the range of 240-300C. When the tetramethylpiperidine compound is added to polyester-forming compositions. it should be able to withstand temperatures on the order of 280C. and up. since such temperatures are required for elficient polymer production. The modifier compounds of this invention do not undergo thermal degradation to produce colored by products or decomposition products having an adverse effect on polyesters such as. for example. causing excessive reduction in polymer molecular weight.

In addition. modifier compounds used to provide the acid dye sites must be compatible with polyesters. The polyester compatibility of the modifier compounds containing the 2.2.(wfvtetramethylpiperidine group has been found to he surprisingly good. These modifier compounds can be reacted with polyesters or polyester-forming compositions at elevated temperatures without the development of objectionable discoloration or adverse reduction of molecular weight.

The 2.1.o.o-tetramethylpipcridine modifier compounds are secondary or tertiary amines having two cs ter-forming groups. each group being attached directly to the piperidine ring or attached to a pipcridinc ring substituent. Where an ester-forming group is attached to a substitucnt ol the piperidine ring. the substituent linkage to the piperidine ring may be. for example. an alkylene. arylene. ether. amide. sulfonamide or striazine linkage. 'Ietramethylpiperidine modifier compounds include piperidine glyeols and their esterlbrniiiig derivatives; piperidine dicarhoxylic acids and their esterforming derivatives: piperidine hydroxyacids and their ester-forming derivatives; and. s-triayine de rivatives containing two ester-forming groups.

As suitable glycol-type modifiers there may he mentioned: l Z-hydroxycthyl )-2.Z.tno-tetramethyl--lhydroxypipcridine; l-( Z-hydroxyQ-methylethyl lloli-tetramethy l--l-hydroxypiperidine; 4- hydroxyl .2.(7.('l-lLl.l"kllTlCth)'l' l -piperidine l -pcntanol; o-l (4-hy droxy-Z.2.(\.o-tetramethyll piperidino )methoxy l -hexanol;

ll l.1.2.6.6-pcntamethyl-4-piperidyloxyl 2-methyl-2- methyl l .3-

propanediol; Z-methyl-Z-l 242.211.6- tetramethy lpipcridino) ethoxymcthyl ll .3- propanediol; l.l p-phenylencdimcthylene his( Z.2.6.o-tetramethyl-4-piperdinol l.l hutenylene ]-bis( 2.2.(i.o-tetramethyl-4-piperidinol I; l.- l'-[ tetrametehylenehisl oxymethylene lbisI 2.2.6.6-tetramethyl-4-piperidino l .8-bis( 2.2.6.6-tetramethylpiperidino )-2.7-octanediol; l.l (tetramethylenediosy )his( 3-[ 2.lob-tetramethylpiperidino I-Lpropanol 2.2 4.o-his( I 2.211.0- tetramethyI-4-pipcridyl I-amino l-x-triazineQ- ylimino|diethanol and the corresponding 1.2.3111- pentamcthyl compound and 2.Z-[ (H 2.2.6.6- tetramethyL-l-piperidylamino) .\'-tria2ine-2.4 diyldiimino] diethanol and the corresponding l1.2.oJi-pentamethyl compound.

As suitable dicarboxylate-type modifiers there may he mentioned: 5-H l.2 .6.o-pentamethyl-4- piperidyloxyl-methyl |-isophthalic acid; ill-(2.2.6.6- tetramethylpiperidinc) ethoxymethyllisophthalic acid. dimethyl ester; 2-[ 2.2.(xo-tetramethyl-4- piperidinyl)sulfamoyl| terephthalic acid. dimethyl cster. the corresponding diethyl ester. acid. and l-methyl derivative and the corresponding carbamoyl com pounds; 4-[ 2.2.(no-tctramethyh lpiperidinyl )sullamoyl] isophthalic acid. dimethyl ester. the corresponding diethyl ester. acid and l-methyl derivative and the corresponding carbamoyl compounds; 5[ 2.2.6.6-tetramethy l4-piperir.linyl) sullamoyll iso phthalic acid. dimcthyl ester. the corresponding dicthyl ester. acid and l-methyl derivative and the correspond' ing carbamoyl compound; 2-[-l-( 3.2.oh-tetramcthyl-4- piperidinylsullamoyl )phenoxyl isophthalic acid. di methyl ester. the corresponding diethyl ester. acid and l-methyl derivative and the corresponding carhamoyl compounds; -l-[ 4-( 2.2.6.o-tetramcthyL-lpiperidinylsullamoylJ-phcnoxy] isophthalic acid. dimethyl ester. the corresponding diethyl ester. acid and lanethyl derivative and the corresponding carhamoyl compounds: 5-[ -l-( 2.2.6.6-tetran1ethy l--lpiperidinylsull'amoyl )phenoxy] isophthalic acid. dimcthyl ester. the corresponding diethyl ester. acid and l-mcthyl derivative and the corresponding carbamoyl Compound; 4-[( 2.2.(Lfi-ILIt'tll1lClll} l lpiperidinyllsulfamoyll-3.(1-naphthalcncdicarhoolic acid. dimcthyl ester. the corresponding diethyl ester. dicarboxylic acid and l-methyl derivative and the corresponding carbamoyl compounds; 4-[(2.2.(1.6- tctramethyl-4piperidinyl)sullamoyll-ZJ- naphthalenedicarboxylic acid. dimethyl ester. the corresponding diethyl ester. dicarboxylic acid and 1- methyl derivative and the corresponding carbamoyl compounds; 2-[ 2.2.6.6-tetramethyl-4- pipcridinyl)sulfamoyl] lluorene-9.-dipropionie acid. dimethyl ester. the corresponding diethyl ester and acid. and l-methyl derivative and the corresponding carhamoyl compounds; and 2.9-di( 2.2.6.6-tetramethyl- 4-piperidyl)decanedioic acid. diethyl ester.

As a suitable hydroxycarboxylate-type modifier there may be mentioned 5-(4-hydroxy-2.2.ob-tetramethyl l piperidine)valeric acid. methyl ester.

As suitable .v-triazine-type modifiers containing two ester-forming groups there may be mentioned: 2.4- dimethoxy-o-l (2.2.6.b-tetramethyl-4piperidyl- )aminol-s-triazine. the corresponding 1.2.2.6.6- pentamethyl compound. and the corresponding 2.4- dihydroxy. l-l-diethoxy. and 2.4-diphenoxy compounds.

Under the polymenforming conditions employed in the practice of the present invention. the tetramethylpiperidine modifiers react and become part ofthe polymer molecule. Their presence in polyester fibers is then permanent and they cannot he removed by washing. dry cleaning. and the like.

The basic nitrogen content of the acid-dyeable poly esters should he at least 0.02% by weight. based on the weight of the modifier polyester. Preferably the weight percent basic nitrogen will be 0.02 to 0.259 and more preferably. 0.05 to 0.15%.

Polymerization accelerators. such as diphenylterephthalate. may be used il'desired. Salts of the tetramethylpiperidinc modifier compounds with acids of phosphorus also may he used in the practice of the invention. Suitable acids include phosphoric acid. diphenylphosphinic acid. phenylphosphonic acid. and the like.

By copolyesters is meant fiber-forming linear eondensation polymers characterized by carhonyloxy linking radicals in the polymer chain and by being prepared using 3 or more reactants. each having 2 ester-forming groups. The copolyesters may. if desired. contain additives. c.g.. dclustrants. viscosity boosters. optical brighteners. toning pigments. antiovidants. and the like. ln addition. filaments prepared from these polymers may enconi pass various cross-sectional configurations such as round. multilohal or hollo\\.

Examples ol linear. fiber-forming condensation poly esters that can he modified in accordance with the present invention are polyethylene terephthalate. polytrimethylene terephthalatc. polylll-dimethylpropy lene tercphthalate). polytetramethylene terephthalate. polyethylene tcrcphthalate/isophthalate (HS/l5). polyethylene tcrcphthalatc/hexahydroterephthalate 10). polylhc\ahydro-p-xylylcncl tercphthalatc. tcrephthalatc copolyesters containing an aliphatic dicarbo\ \lic constituent (especially tcrcphthalatc :alipalc copolycstcrsl and tcrcplithalatc coacid polyesters containing a branched-chain glycol constituent (especially ethylene/Z.Z-dimethylpropylene terephthalate copolyesters). Fibers or filaments of modified terephthalate copolyesters are a preferred embodiment of the present invention.

The practice of this invention is particularly important with respect to providing acid-dyeable fibers or filaments of copolyesters containing at least 85 mol percent of ethylene terephthalate units. Filaments of copolyesters such as. for example. tcrephthalate/adipate copolyesters retain a relatively high level of their dyeability when subjected to heat-setting treatments after they have been drawn.

As indicated above. copolymer compositions containing the 2.1.6.6tetramethylpiperidine group are basic compounds and. as such. have a relatively high affinity for acid dyes and can be dyed in a range of colors. As illustrations of such acid dyes. there may be mentioned C.l. Acid Blue (CI. 62055). C.l. Acid Red 4 (CI. 14710). (.l. Acid Yellow (Cl. 18950). and Cl. Acid Green 25 (CI. (11570). Fibers of these polymer compositions can be combined with other polyester fibers to provide fabrics that can be dyed to multicolors in a single dye bath. in general. the dyed fi bers of the present invention have good dye lightfastncss.

The dyeability of the filaments of this invention may be determined by measuring the amount of dye left in the dye bath after dyeing in a standard manner. The whiteness of the filaments may be measured by means known to those skilled in the art. for example. reflectance determination using a reflectometer. In general. whiteness will improve as the purity of the compounds used is improved and will improve by following known practices for avoiding degradation and by minimizing the exposure of the compositions to oxygen at elevated temperatures. If desired. toners and brighteners can be added to increase fiber whiteness.

The polyester compositions used in this invention usually will have a relative viscosity between 7.5 and preferably the relative viscosity will be from about 1 1 to about 30. The relative viscosity is determined by measuring the ratio of the viscosity of a solution containing 4.75% by weight of the polymer. in hexafluoroisopropanol containing parts per million. by volume. of concentrated sulfuric acid, to the viscosity of the hexafluoroisopropanol sulfuric acid solvent measured in the same units at 25 i0.(15C.

The nitrogen content of the modified polyesters is determined using the micro Kjeldahl method of analysis. Where the value determined includes nitrogen other than nitrogen from the piperidine ring. i.e.. non-basic nitrogen. the basic nitrogen content is calculated by multiplying the measured nitrogen content by the frac tion ofthe total number of nitrogen atoms in the moditier that are piperidine ring nitrogen atoms.

In the procedures and examples that follow. all percentages given are by weight based on total weight except as indicated otherwise. and in the examples all scour and dye baths use a bath-to-fabric weight ratio of 40:1. except as indicated otherwise. and the wetting agent used is octylphenol condensed with 9-10 moles of ethylene oxide. Also. the expression "cut to flake and solidpliase polymerized-- means the polymer was cut to flake in an Abbe rotary cutter (Abbe Engineering Co.. New York. New York] and passes through a metal having holes 0.125-inch perforated screen (0.3 l X-centimeter) in diameter and this flake is solidphase polymerized by heating it at 190C. at less than 5 torr. except as indicated otherwise. for the indicated period of time. If the flake is stored. rather than used following its preparation, it is dried prior to spinning. Unless otherwise indicated. the dye carrier used in the examples is a composition comprising about 507! methyl p-toluate. 25% methyl benzoate and 25% biphenyl.

Filaments prepared in the examples have a low level ofcolor; that is. while they are not pure white. the color is acceptable.

PREPARATION OF TETRAM ETHY LPlPERlDlNE MODIFIERS Representative procedures for preparation of 2.2.6.o-tetramethylpiperidine modifiers for use in the practice of this invention are given below:

I. 1-( Z-Hydroxyethyl )-2.2.6.o-Tetramethyl-4- Hydroxypiperidine Method (A) A sample of 157 grams of 2.2.bfi-tetramethyL-lhydroxypiperidine is placed in a 400-milliliter stainless steel bomb. which is cooled to 7HC. The bomb is evacuated. filled with nitrogen at atmospheric pressure. and reevacuated. The bomb is placed on a scale and connected to a supply of ethylene oxide by a flexible tube. Ethylene oxide is allowed to pass into the bomb until the increase in weight is 52 grams. The bomb is then sealed and disconnected from the ethylene oxide supply. The bomb is held at l 10C. for 1 hour. C. for 1 hour. C. for 1 hour and at l55-1h0C. for 4 hours. The bomb and charge are cooled. and 204 grams of product are removed. The crude material is sublimed twice at C. at a pressure of less than 1 torr to give 1-( Z-hydroxyethyl )-2.2.b.b-tetramethyl-4- hydroxypiperidine as a white product melting at lt'l()l83C.

Method (B) In a heavy-wall. polymer tube is placed 2.2.6.6- tetramethyl-4-hydroxypiperidine and Z-chloroethanol in a molar ratio of 1 to 3. The tube is purged with nitrogen. evacuated and sealed. It is then heated in a salt bath at C. for 1 hour. The contents become a clear solution at l30140C. and start forming the hydrochloride salt at l50160C. At the end of the heating period. the seal of the tube is broken and the contents repeatedly washed with ether to remove the unreacted piperidine. The hydrochloride salt is then dissolved in water and the solution made strongly basic with aqueous potassium hydroxide and extracted 4 times with ether. The four ether layers are combined. dried over potassium carbonate and the ether distilled. The solid. a combination of the unreacted piperidine and the 2- hydroxyethyl derivative. is purified by sublimation. The unreacted piperidine is removed by sublimation at 100C. at about 0.1 torr. The remaining solid is the 1- (Z-hydroxyethyl )Z.1.6.b-tetramethyl-4- hydroxypiperidine and is sublimed at 135C. at about 0.1 torr. The sublimed product melts at 169 to 174C.

To a 400-milliliter stainless steel bomb is added 1 17.5 grams of 2.2.6.6-tctramethy l4 hydroxypiperidine. The bomb and charge are cooled to 78C. and the bomb is evacuated: filled with nitrogen at atmospheric pressure and recvaculated. A dropping funnel is attached to the bomb and 60 grams of 1.2- propylene oxide is added. as determined by the weighing of the bomb before and after the addition. The bomb is then sealed and held at 110C. for 1 hour. 125C. for 1 hours. 140C. for 1 hour and l55160C. for 8 hours. The bomb is then cooled and 164 grams of product is removed. This product is placed in a flask and the pressure reduced to permit the removal of 6 grams of excess propylene oxide yielding 158 grams of 1-( Z-methyl-lhydroxyethyl )-2.2.6.o-tetramethyl-4- hydroxypiperidine.

III. 1.1 p-Phenylenedimethylene) Bis( 2.2.6.fi-Tetramethyl-4-Piperidinoli In a 500 milliliter. round-bottomed flask are placed 1 1.4 grams ofa.a'-dibromop-xylene, 25.2 grams of 2.- 2.6,fi-tetramethyl-4-hydroxypiperidine and 120 milli liters of diglyme (dimethyl ether of diethylene glycol). The contents are refluxed for 19 hours with vigorous stirring and filtered hot. The diglyme from the filtrate is removed by distillation. The remaining solid is washed with methanol. The solid is then washed repeatedly with ether. The l.l'-(p-phenylenedimethylene1 bis(2.2.6.b-tetramethyl-4-piperidinol) is obtained as a white crystalline solid. is dried in a vacuum oven and has a melting point of 237239C.

IV. 1.1 Z-Butenylene) Bisl 2.lbb-Tetramethyl-4-Piperidinol) la a 500-mi1liliter. round-bottomed flask are placed 21.4 grams of l.4-dibromo-2-butene. 63 grams of 2.2.- 6.6-tetramethyl-4-hydroxypiperidine and 200 milliliters of diglyme. The contents are refluxed for 3.5 hours and filtered hot. The diglyme in the filtrate is removed by distillation. The remaining solid is then washed with water. The solid is then dissolved in methanol treated with activated charcoal and filtered. Methanol is removed from the filtrate. The off-white. crystalline solid is dissolved in an acetone/methanol mixture. treated with activated charcoal and filtered. The solvent from the filtrate is removed on a rotary evaporator. The 1.1 2-butenylene) bis( 2.2.6.6-tetramethyl- 4-piperidinol) is obtained as a white crystalline solid which is dried in a vacuum oven at 80C. and found to melt at 204C.

V. 2.2 '-l 4.6-bisl 2.2.6.(w-Tetramethyl4- Pipcrid l lamino )-.v-'l"riazine-2-Ylimino ldiethanol la a 1 liter. round-bottomed flask are placed 36.9 grams of cyanuric chloride. 100 milliliters of acetone and 50 milliliters of water. This is cooled to 5C. To this mixture are added 21 grams of diethanol amine and a solution ofll grams ofNaOH in 50 milliliters of water. The contents of the flask are stirred at 05C. for onehalf hour. filtered cold and washed with water. A yield of 34 grams of crude 2.2'-(4.fi-dichloro-s-triazine-2- yliminoJ-diethanol is obtained. The material is recrystallized from methanol to have a melting point of In a 300-niilliliter. round-bottomed flask are placed 6.3 grams of 2.2'-(4.6-dichloro-rtriazinc-Z-ylimino) diethanol. 100 milliliters of dioxane and 7.8 grams of 4amino-2.2.o (-tetraniethylpiperidine. The contents are refluxed for 1 hour and filtered. The white crystalline solid is dissolved in water and excess NaOH added. White crystals separate and they are filtered and washed with water. The yield is 5.5 grams of 2.2'-[4.6- bis( 2.2.6.6-tetramethyl-4-piperidyl lamino l-s-triazine- Z-yliminoldiethanol as white crystals melting at 12 1 to 1 22C.

VI. 5-[( 2.2.bb-Tetramethyl-4-Piperidinyl)sulfamoyl1- lsophthalic Acid. Dimethyl Ester A 2-liter flask is fitted with a reflux condenser. drying tube, thermometer. and mechanical stirrer. To this is added 300 milliliters of thionyl chloride and I5 milliliters of dimethyl formamide. With stirring. 296 grams of the sodium salt of S-sulfoisophthalic acid, dimethyl ester. is added portionwise. The mixture of solids and liquid is heated to reflux for 3 hours at which point 600 milliliters of benzene is added. Heating is continued for minutes. the solution allowed to cool. and the precipitated sodium chloride removed by filtration. The benzene and excess thionyl chloride are stripped under vacuum and the residue is taken up in 475 milliliters of hot benzene. The insolubles are filtered off and the sol vent again removed under vacuum. The residual crude sulfonyl chloride is crystallized from a mixture of henzenehexanc to yield 246 grams of S-(chlorosulfonyl- )isophthalic acid. dimethyl ester as off-white needles melting at 1 15 to l 19C.

To a solution of 39 grams (0.25 mole) of 4-amino- 2.2.bb-tetramethylpiperidine in 300 milliliters of methylene chloride. is added dropwise 80 grams (0.27 mole) of 5-(chlorosulfonyl)isophthalic acid. dimethyl ester. dissolved in 200 milliliters of methylene chloride. The reaction is mildly exothermic and the reaction temperature is maintained below C. by means of a water bath. The white hydrochloride salt precipitates during the addition.

After stirring overnight. the hydrochloride salt is collected by filtration. washed with methylene chloride and dried. The dry hydrochloride salt is slurried in 500 milliliters of methanol and neutralized by the addition of 13.7 grams of sodium methylate. After stirring for 30 minutes. the product is collected by filtration. washed with milliliters of methanol followed by three 50- milliliter portions of water and finally by a -milliliter portion of methanol.

This crude product is placed in a Soxhlet thimble and continuously extracted with methanol for 2 days. The crystals in the pot were collected and recrystallized from an ethanol-hexane mixture to yield 88 grams (78); of pure Compound VT as very fine. white crystals. melting at 223 to 224C.

Vll. S-ll l.2.2.fib-PentamethyL-l-Piperidinyl )sulfamoyl llsophthalic Acid. Dimethyl Ester To a solution of (1.8 grams (0.04 mole) of -laminol.2.2.o.6-pentamethylpiperidinc in 50 milliliters of methylene chloride. is added dropwise. over 30 minutes. l 1.7 grams (0.04 mole) of ichlorosulfonyllisophthalic acid. dimethyl ester. dissolved in -10 milliliters of methylene chloride. The reaction is mildly exothermic and the reaction temperature is maintained between 25 and 30C. by means of a water bath. A white precipitate of the hydrochloride salt forms during the addition.

After stirring overnight. the hydrochloride salt is neutralized by addition of aqueous potassium carbonate. The phases are separated. the methylene chloride phase dried with anhydrous Nll- S() and the solvent stripped under vacuum. The white residue is crystal lizcd from ethanol-hexane to yield 1 1.5 grams (1W of Compound V11 as white crystals melting at 143" to 1451'.

V111. -1 2.2.o.o-TetramethyL-l-Piperidinyl )sullamoyl 1' lsophthalic Acid. Diethyl Ester To a solution of 26.5 grams (0.17 mole] of 4-amino- 2.2.h.(i-tetramethylpiperidine in 200 milliliters of methylene chloride. is added dropwise 54 grams (0.185 mole) of 5-tchlorosnlfonyl)isophthalic acid. dimethyl ester. dissolved in 150 millil ters of methylene chloride. The reaction temperature is maintained below 30C. by means of a water bath After stirring overnight. the white hydrochloride salt is collected by filtration. washed with methylene chloride. and dried.

The solid is transferred to a 2-liter flask. About 1.5 liters o1- absolute ethanol is added along with about 50 grams of potassium carbonate. The mixture is heated to a boil for 1 hour with any loss of solvent being made up by the addition of fresh ethanol. The ethanol is then decanted. about 1 liter is added to the residual solids and the heating process is repeated. The remaining solid is filtered off. the combined ethanol extract evaporated to dryness under vacuum and the residue slurried in water. The mixture is filtered and the crude sulfonamide crystallized from ethanol to yield 45 grants (129i 1 of Compound Vlll as white crystals melting at 179 to IX. 5-1t2.2.6.6-'Tetramethyl-4-Piperidinyl)sull'amoyl]- lsophthalic Acid To a stirred solution of 400 milliliters of 5 N KOH is added 100 grams (0.22 mole) ofthe hydrochloride salt of 5-112.2.bfitetramethyl-4 piperidinyl)sulfamoyllisophthalic acid. dimethyl ester. As the ester hydrolyles the sulfonamide gradually goes into solution. The hydrolysis is exothermic. The reaction temperature is kept below C. by addition of ice to the flask. After stirring minutes. the solution is filtered and the hitrate acidified to about pH 4 at which point the diacid precipitates as a white solid. This is collected. washed with water. redissolved in aqueous potassium bicarbon ate. filtered and reprecipitated by the addition ofaeetic acid. Collection of the solid. washing with water. and drying under vacuum at 100%. yields 74 grams (83"?) of Compound 1X as a white powder melting at 381'C.

X. 5-11 1.2.2.(1.tiPcntamethyl-4- Piperidinyl lsullamoyl- |lsophthalic Acid To a stirred solution of 250 milliliters of 5 N KOH is added grams of the hydrochloride salt of 5 l( l.2.2.h.(w pentamethyl-l-piperidinyl )sullhmoyl lisophthalic acid. dimethyl ester. As the ester hydrt 1y yes. the sulfonamidc gradually goes into solution. The reaction temperature is kept below 15C. by addition of ice to the flask. After stirring 25 minutes. the solution is filtered and the filtrate acidified to about pH 4 Ill (ill

at which point the diacid precipitates as a white solid This is collected. washed with water. redissohed in aqueous potassium bicarbonate. filtered and reprecipitated by the addition of acetic acid. Collection of the solid. washing with water and drying under vac uum at 100C. yields 20.7 grams of the partially hydrated Compound X as a white powder having a melting point of 324C.

X1. 1t2.2.6.6-TetramethyL4- Piperidinyl )Sulfamoyl lFluoroenc-Jfi-Dipropionic Acid. Dimeth yl Ester To a stirred mixture of 50 milliliters of thionyl chlo ride and 1 milliliter of dimethyl formamide is added 13.2 grams of the sodium salt of a mixture of isomers of sull'o-iluorene-9.Q-dipropionic acid. dimethyl ester. and the resulting slurry is then heated to retlu\ for hours. The excess thionyl chloride is then removed under vacuum. The residue is treated with 150 milliliters of hot benzene and the insoluble sodium chloride is filtered ofl. The benlene is stripped and the crude sulfonyl chloride is crystallized from a mixture of ben- Iene-hcsane to yield 9.5 grams of an isomer mixture of chlorosulfonyl-fluorene-9.9 dipropionic acid. dimethyl ester. as off-white crystals melting at 142 to 143C To a solution of 3.0 grams (0.019 mole) of 4-amino- 2.2.b.h-tetramethylpiperidine in 30 milliliters of methylene chloride. is added dropwise 8.5 grams of the isomer mixture of (chlorosulfonyl )fluorene-9.9- dipropionic acid. dimethyl ester. dissolved in 30 milliliters of methy lene chloride. The reaction is mildly exo thcrmic and the reaction temperature is maintained below 30C. by means of a water bath. A heavy white precipitate forms during the addition.

After stirring overnight. this hydrochloride salt is collected by filtration. washed with methylene chloride and dried to yield 104 grams (U194 of product. The hydrochloride salt is slurried in 200 milliliters of methanol and neutralized by the addition of 0.95 gram of sodium methylate at which point the free base goes into solution. The methanol is removed under vacuum and the residue slurred in water. The product is filtered off. dried and cry stallized from ethyl acetate-hexane to yield 7.5 grams (7771 of Compound X1 as white crys tals melting at 130 to 132C.

X11. N.N'-l (w-t l2.2.6.(i-Tetrainethyll-Piperidyl ]amino l-sl'ria7.ine-2.4-diylldiglycine To 350 milliliters of ice water is added (11.5 grams of cyanuric chloride dissolved in hot acetone. The resu1 tant slurry is kept below 10C. while 53 grams of 4- amino-2.2.(1,(i-tetrai1ietliylpiperidine is added. This is followed by 17.7 grams of sodium carbonate dissolved in a small amount of water. The resulting mixture is stirred for 1.5 hours while maintaining the temperature between 0 and 5C. The solid is collected. washed with water. and dried under vacuum at C. to yield 97 grams of 2.4-dichloro-6-t 2.2.(i.h.-tetramethyl-4- pipcridylamino)-.s-triazine as a white powder.

To a suspension of (i1 grams of this dichloroamino triaz ine in (v00 milliliters of a water-ice mixture is added dropwise over 20 minutes a solution containing solids dissolve by the end of the addition. l he mixture is stirred overnight.

The mixture is then heated to reflux for 2 hours. cooled and filtered. The filtrate is made acidic with dilute hydrochloric acid and then brought up to about pH 4 by the addition of sodium carbonate to precipitate the product as a fine. white solid. This is collected by filtration and washed with water. This crude product is reprecipitated once by dissolving in aqueous potassium carbonate followed by careful acidification to about pH 4 with dilute hydrochloric acid. The solid is dried under vacuum at 100C to hield 46 grams (56% of N.N'-| 6- I 2.2.6.6-tetramethyl-4-piperidyl ]amino J-s-triazine- 2.4-diyl]diglycine melting at 385C.

Xlll. 2.9-Di( 2.2.6.6-'letrarnethyl-4-Piperidyl )Decanedioic Acid. Diethyl Ester Ethyl-(x-cyanin 2.2.6.o-tetramethylpiperidine-1'41) acetate. hydrochloride salt The general procedure employed is that of McElvain and Lyle (J. Amer. Chem. Soc.. 72. 384 (1950).

A mixture of 23.3 grams (0.15 mole) of 2.2.6.6- tetramethyl-4-piperidine. 25.5 grams (0.22 mole) of ethyl cyanoacetate. 2.4 grams ammonium acetate. 6.9 grams glacial acetic acid and 150 milliliters of benzene is heated at reflux in a Dean Stark apparatus until the theoretical amount of water is collected in the trap (3-4 hours). The dark solution is cooled. 150 milliliters of ether added. and the solution saturated with gaseous hydrogen chloride. The precipitated salt is filtered. washed with ether and vacuum dried to give 36.5 grams (85% yield) of a light tan solid. Recrystallization from absolute ethanol produced colorless crystals melting at 239C.

Ethyl-a-eyanoi 2.2.6.6-tetramethylpiperidine A .u )acetate Five grams (0.107 mole) ofthe above salt is dissolved in 40 milliliters of water. the solution made alkaline with solid sodium carbonate. and the product salted out with sodium chloride and extracted into ether. The ether layer is dried (4A molecular sieves). and on solvent removal a yellow oil is obtained. which crystallires on cooling and trituration with petroleum ether to give 3.8 grams (87? yield) of a white solid melting at 62 to 64C.

Ethyl-u-cyanoi 2.2.6.6tetramethyl-4- piperidine )acetate A solution of 17 grams (0.068 mole) of ethylv cyano-(2.2.6.h-tetramethylpiperidine \.u) acetate in 200 milliliters of sodium-dried ethanol. which has been purged with nitrogen. is hy drogcnated at C. and one atmosphere of hydrogen over 3 grams of 1091' palladium on charcoal for a period of 3.5 hours in an efficiently stirred vessel. Removal of the catalyst and evaporation of the solvent gives a pale yellow oil. which is passed down a short column of \Noelm neutral alumina and eluted with benzene. Solvent evaporation gives 16.0 grams (93? yield) of ethyl-a-cyano( 2.2.6.6- tetramethyl--l-piperidine) acetate boiling at 120C. at l l torr.

Diethyl-2.)-dicy ano-2. )di( 2 .2.6.6-tetramcthyl 4- piperidine) decanoate A solution of 12.5 grams (0.05 mole) of ethyl-o cyano-( 2.2.6.6-tetramethyl-4-piperidineJ acetate in milliliters ofdry dimethyl sulfoxide is charged to a flame-dried. nitrogen-flushed reactor which in turn is connected to an appropriate device for measuring hydrogen evolution. One and two-tenths grams (0.05 mole) of neat sodium hydride is added in portions to the stirred solution. which is maintained at about 20C. until hydrogen evolution ceases. A solution of 5.3 grams (0.026 mole) of 1.6-dibromohesane in 10 milliliters of dry dimethyl sulfoxide is added dropwise. and the resulting suspension maintained below 35C. until addition is complete. The mixture is then stirred overnight at room temperature and under a slow nitrogen purge. The yellow solution obtained is poured into 700 milliliters of ice water and the cream precipitate is iso lated by filtration. dissolved in methylene chloride. washed with water and dried over 4A molecular sieves. Evaporation of the solvent gives the product as a white crystalline solid (11 grams. 75.1% yield). melting at 162 to 164C.

2.9-bis(2.2.6.6-tetramethy1-4- piperidine )decanedinitrile A warm solution of 3.7 grams (0.066 mole) of potassium hydroxide in milliliters of ethylene glycol is added to l 1.72 grams (0.02 mole) of diethyl-2.9- dicyano-2.9-bis( 2.2.6.6-tetramethyl-4-piperidinel decanoate and the mixture is heated at rellux for 3 hours. The cooled solution is then poured into 230 milliliters ot'cold water and thoroughly extracted with portions of methylene chloride. After drying (4A molecu lar sieves). the solvent is removed to give 8.15 grams (92% yield) ofa white crystalline solid. melting at 133 to l 35C.

2.9-Di( 2.2.6.6-tetramethyl-4-piperidyl )decanedioic acid. diethyl ester A mixture of 25 grams (0.057 mole) of 2.9 bist 2.2.6.6-tetramethyl-4-piperidine ldecanedinitrile and 150 milliliters ofconcentrated hydrochloric acid is heated at reflux for 20 hours. Evaporation of the water leaves a sticky residue from which the last traces of water are removed by azeotropic drying (benzene). 'l'wo-hundred milliliters of absolute ethanol and 5 milliliters of concentrated sulfuric acid are added and the mixture is heated at reflux for 18 hours. The solvent is removed in vacuo. the residual material rendered alkaline with anhydrous potassium carbonate. and the product thoroughly extracted with methylene chloride and dried over 4A molecular sieves. Removal of the solvent in vacuo giyes 30 grams of an orange oil. whose infrared spectrum shows. in addition to the product. bands indicative of an amide function.

The oil is subjected to chromatography on Woelm neutral alumina and the column eluted with bemenechloroform mixtures of increasing polarity. The fraction from 3:2 benzene:chloroform is the major fraction and monitoring by infrared reveals essentially complete loss of the amide band. Solvent removal goes 21.5 grams (70.4'1 yield) of 2.9-dil2.2. xh-tetramethyl--l piperidyl)dccaucdioic acid. diethyl ester. as a strawcolored. thick oil. lhermal analysis estimates the boil ing point as XIV. 2.4-Dimethoxy-6-[ 2,2.6.6-Tetramethyl-4-Piperidyl amino ]-s-Tria7.ine

In a 200milliliter. round-bottomed flask are placed 60 milliliters of dioxane and 4.4 grams of 2.4- dimethoxy-6-chloro-s-triazine. which can be prepared as described by Dudley et al.. J. Amer. Chem. Soc.. 73. 2986 (1951 To this is added 3.9 grams of 4-amino- 2.2.6.6-tetramethylpiperidine at room temperature. A white precipitate is formed as soon as the reactants are mixed. The contents are stirred vigorously at room temperature for 20 minutes and then filtered. The white crystals are dissolved in water. excess aqueous NaOH added and the solution extracted twice with ether. The ether solutions are heated on a steam bath to remove the ether, leaving 2.4-dimethoxy-6- 2.2.6.6-tetramethyl-4-piperidyl)-amino]-.r-tria2ine as a white crystalline solid; the yield is 4.4 grams and the crystals melt at 167 to l68C.

XV. 2.4-Dimethoxy-6-[( l.2,2.6,6'Pentamethyl-4- Piperidyl )-amino l-s-Triazine In a 200-milliliter. round-bottomed flask are placed 3.3 grams of 2.4-dimethoxy6-chloro-s-triazine and 70 milliliters of benzene. To this are added 3.2 grams of 4-aminol.2,2.6.6-pentamethylpiperidine and the contents refluxed for 3 hours. A white precipitate separates and it is filtered and discarded. The filtrate is maintained at room temperature for 1 week. A white crystalline precipitate separate. It is filtered. dissolved in water. excess aqueous Na CO added and extracted twice with ether. The ether solution is heated on a steam bath to remove the ether. leaving a small amount of 2.4-dimethoxy-6-H 1.2.2.6.6-pentamethyl-4- piperidyl )-amino .s'-tria7.ine as a white crystalline solid; the yield is about 0.2 to 0.3 gram and the crystals melt at 143 to 145C.

EXAMPLE 1 This example illustrates the hydroxyethyl)-2.2.6.6-tetramethyl-4- hydroxypiperidine. Compound I. in preparing aciddye-able copolyester filaments.

A. A mixture of 75 grams of polytetramethylene terephthalate. as flake with a relative viscosity of 66.5 and 0.90 gram of Compound 1 is placed in a polymer test tube. and the tube evacuated and filled with nitrogen 5 times. The tube is equipped with a rubber stopper. A stainless steel tube passes through the center of the stopper and carries a short section of rubber tubing at its top. The rubber tubing is lubricated with mineral oil and is passed over the shaft of a helical stirrer. The stopper also carries a second stainless steel tube for the passage of gas. The polymer is melted and the mixture is blended for minutes under nitrogen. The blended polymer is cooled. cut to flake and solid-phase polymerized for 6 days.

use of l-(2- The flake is then spun into a S-fllament yarn at a pack-block temperature of 232C. and a spinneret temperature of 232C. The filaments have a relative viscosity of 16.9 and contain 0.095% nitrogen.

The yarn is drawn 3X in two stages. The yarn passes from a feed roll at 21.7 yards 19.8 meters) per minute. over a pin heated at 85C. at yards (45.7 meters) per minute. over a second pin heated at 73C. at 65 yards (59.4 meters) per minute and is wound up at 63 yards (57.6 meters) per minute. The resulting yarn has a denier of 41. a tenacity of 1.1 grams per denier and an elongation of 82.4%. The yarn is knit into fabric.

The fabric is scoured for 30 minutes at the boil in a bath containing l/( of wetting agent and 1% of tetrasodium pyrophosphate and rinsed with hot water.

The fabric is dyed in baths having a pH of 3.0 and 6.0 at 121C. in a pressure dyer with dye carrier. Each bath contains 2% owf ofC.l. Acid Blue 25 (CI. 62055) and 15% owf of dye carrier. The fabrics are held in the baths for minutes. The dyed fabrics are scoured 30 minutes at 82C. in a bath containing. by weight, 1'71 of the wetting agent and 0.5% acetic acid. The fabric dyes to a deep shade of blue at pH 3.0 and to a light shade at pH 6.0.

8. ln a separate experiment. 7.5 grams of Compound I and 500 grams of a polyethylene terephthalate prepolymer powder with a relative viscosity of 3.2 are mixed in a two-liter, three-necked flask. The flask is evacuated and re-fllled with nitrogen five times. The charge is melted under nitrogen at 283C. the pressure is slowly reduced to less than 1 torr and the charge is stirred under these conditions for 55 minutes. The polymer is cooled under nitrogen and cut to flake. The flake has a relative viscosity of 19.3, and contains 0.10% nitrogen.

The flake is dried and spun to a l7-fllament yarn at pack block and spinneret temperatures of 285C. and the yarn is wound up undrawn at 300 yards (273 meters) per minute. The yarn is drawn 4.8x in two stages. The yarn passes from a feed roll at 50 yards (45.5 meters) per minute over a hot pin at 70C. to a first-stage roll at 157 yards (143 meters) per minute. over a hot plate at C. and to a second stage roll at 241 yards (220 meters) per minute. The yarn is then wound up at 240 yards (218.4 meters) per minute. The resulting 50- denier yarn has a tenacity of 3.7 and an elongation of 1571. Three yarns thus prepared are plied and knit into fabric. The fabric is scoured and dyed at pH 3.5 using the procedure described above. The fabric dyes to a light shade.

EXAMPLE 2 This example illustrates the use of 1-(2-hydroxy-2 methylethyl )-2.2.6.6-tetramethyl-4-hydroxypiperidine, Compound 11. in preparing acid-dyeable copolyester filaments.

Polymer is prepared in a polymer test tube from 60 grams of a copolymer having a relative viscosity of 19.6 and 0.77 gram of Compound ll. The copolymer has 94 mole percent of ethylene terephthalate units and 6 mole percent ethylene adipate units. The contents are purged with nitrogen and evacuated. the cycle being repeated 4 times. The contents are then heated at 255C. under nitrogen until melted. stirred for 0.5 hour at 255C. and then heated at about I torr at 255C. for 1 hour. The polymer is cooled and cut to flake. The flake contains 0.07% nitrogen. The flake is solid-phase polymerized for 90 hours at C. at not over 1 torr. The resulting polymer has a relative viscosity-of 49.0.

The polymer is spun into a 5-l'ilament yarn at a block temperature of 270C. and a spinneret temperature of 268C. and is wound to a package at 1 1.7 yards 10.7 meters) per minute.

The yarn is drawn 4.5X. The yarn passes from a feed roll at 16.7 yards 15.3 meters) per minute. over a pin heated at 83C.. to a draw roll at 75 yards (68.6 meters) per minute and wound up at 74 yards (67.7 meters) per minute. Two yarns produced as above are plied. The plied yarn has a denier of 76. a tenacity of 3.8 grams per denier and an elongation of 21.9%. The yarn is knit into fabric. which is scoured and dyed using the procedure described in Example 1. The fabric dyes to a medium shade of blue.

EXAMPLE3 This example illustrates the use of l.l-(2- butenylene) bis( 2.2.6.6-tetramethyl-4-piperidinol Compound IV. in preparing acid-dyeable copolycster filaments.

Sixty grams of dry. previously prepared. polyethylene terephthalate containing copolymerized adipate units corresponding to 5.5 mole percent adipic acid is placed in a polymer test tube. To this are added 1.3 grams of Compound lV. The polymer test tube is provided with a rubber stopper. a stirrer and a glass tube. The contents are purged with nitrogen and evacuated; the process repeated 4 to 5 times. The contents are then heated until melted at 255C. under nitrogen. about 20 minutes. stirred under nitrogen for 0.5 hour and then for 1 hour at a pressure of less than 1 torr. The polymer is then put under nitrogen and cooled. The polymer is cut to flake. The flake contains 0.13% nitrogen.

The flake is then solid-phase polymerized at 190C. for 160 hours at a pressure ofless than 1 torr. The polymer has a relative viscosity of 34.7.

The flake is then melted and spun into a 5-filament yarn at a block temperature of 267C. and a spinneret temperature of 270C. and wound to a package. In a separate step. the yarn is drawn 4.5X on a hot pin at 85C. at a draw roll speed of 75 yards (68.6 meters) per minute. The drawn yarn is then two plied. The twoplied yarn has a denier of 74.3. a tenacity of 3.0 grams per denier and an elongation of 27%.

The yarn is knit into fabric which is scoured and dyed using the procedure described in Example 1. Dycings are made at pH 3.0 and 4.5 and the fabric dyes to a medium shade of blue.

EXAMPLE 4 This example illustrates the use of 2.2[4.6' bis( 1 2 .2.6,o-tetramethyl-4-piperidyl ]amino )-.s-triazine- 2-ylimino]-diethanol, Compound V. in preparing aciddyeable copolyester filaments.

A dry ethylene terephthalate polyester having a rela tive viscosity of 30.8 and containing about 5.5 mole percent adipate units is placed in a polymer test tube. The tube is provided with a rubber stopper carrying a stirrer. a glass tube and another glass tube connected with a rubber tube to a test tube containing 2.8 grams of Compound V. The contents are purged with nitrogen and evacuated; the process being repeated 4 times. The contents of the polymer tube are then heated until melted at 255C. under nitrogen. about 20 minutes. Compound V is added and the mixture is stirred under nitrogen at 255C. for 0.5 hour. The polymer is then put under nitrogen and cooled. The polymer is cut to flake and the nitrogen content determined. The polymer is calculated to contain 0.1 1% basic nitrogen. The flake is solid-phase polymerized at 190C. at a pressure of less than 1 torr for 190 hours and this product is found to have a relative viscosity of 12.2.

The polymer is then spun into a S-fllament yarn at a spinning block temperature of 245C. and a spinneret temperature of 245C. and wound to a package. The spun yarn is drawn over a hot pin at C. The draw ratio is 2.0 and the feed roll speed is 16.7 yards l5.3 meters) per minute. Two of the drawn yarns are plied and skeins scoured and dyed at pH 3.0 and 4.5. using the procedure described in Example l. Both skeins dye to a dark blue shade.

EXAMPLE 5 This example illustrates the use of 5-[(2.2,6.6- tetramethyl-4-piperidiny1)sulfamoyl]isophthalic acid. dimethyl ester. Compound VI in preparing aciddyeable copolyester filaments.

A dry ethylene terephthalate polyester having a relative viscosity of 19.5 and containing about 5.5 percent adipate units is placed in a polymer test tube with 2.5 grams of Compound V1. The tube is provided with a rubber stopper carrying a stirrer and a glass tube. The contents are purged with nitrogen and evacuated; the process being repeated 4 times. The contents are then heated until melted at 255C. under nitrogen. about 20 minutes. stirred under nitrogen at 255C. for 0.5 hour and then stirred for l hour at 225C. at a pressure of less than 1 torr. The polymer is then put under nitrogen and cooled. The polymer is cut to flake and the nitrogen content determined. The polymer is calculated to contain 0.1 1% basic nitrogen. The flake is solid-phase polymerized at C. at a pressure of less than 1 torr for 1 13 hours and this product is found to have a relative viscosity of 17.1.

The polymer is then spun into a 5-filament yarn at a spinning block temperature of 257C. and a spinneret temperature of 248C. and wound to a package. The spun yarn is drawn over a hot pin at 83C. The draw ratio is 4.5 and the feed roll speed is 16.7 yards 15.3 meters) per minute. Two of the drawn yarns are plied. The plied yarn has a denier of 56.5. a tenacity of 2.3 grams per denier and an elongation of 34%. The plied yarn is knit to a fabric and the fabric scoured and dyed at pH 3.0 and 4.5 using the procedure described in Example l. Both fabrics dye to a dark shade of blue.

EXAMPLE 6 This example illustrates the use of a reduced amount of Compound VI in preparing filaments of an aciddyeable copolyester.

A dry ethylene terephthalate polyester having a relative viscosity of 19.5 and containing about 5.5 mole percent adipate units is placed in a polymer test tube with 1.5 grams of Compound V1. The tube is provided with a rubber stopper carrying a stirrer and a glass tube. The contents are purged with nitrogen and evacuated; the process being repeated 4 times. The contents are then heated until melted at 255C. under nitrogen. about 20 minutes. stirred under nitrogen at 255C. for 0.5 hour and then stirred for l hour at 255C. at a pressure of less than 1 torr. The polymer is then put under nitrogen and cooled. The polymer is cut to flake and the nitrogen content determined. The polymer is calculated to contain 0.0971 basic nitrogen. The flake is solid-phase polymerized at 190C. at a pressure of less than torr for l 13 hours and this product is found to have a relative viscosity of 33.3.

The polymer is then spun into a 5-filament yarn at a spinning block temperature of 255C. and a spinneret temperature of 260C. and wound to a package. The spun yarn is drawn over a hot pin at 80C. The draw ratio is 2.5 and the feed roll speed is 16.7 yards 15.3 meters) per minute. Two of the drawn yarns are plied.

the preparation of acid-dyeable polyester filaments: S- l( l.2 2.6.(i-pentamethyl-4-piperidinyl )sulfamoyllisophthalic acid. dimethyl ester. Compound VII; 5- [(2.2,6.o-tetramethyl-4-piperidinyl )sulfamoyl]isoph- The plied yarn has a denier of 64. a tenacity of 1.8 5 thalic acid, diethyl ester. Compound Vlll; 5-[(2.2 6 6- grams per denier and an elongation of 597:. The plied tetramethyl-4-piperidinyl)sulfamoyll-isophthalic acid.

yarn is knit to a fabric and the fabric scoured and dyed Compound IX; 5-[( l.226,6-pentamethyl-4- ill pH 1 n ing he procedure l'i ed in E piperidinyl)sulfamoyl ]isophthalic acid. Compound X;

ample 1. At pH 3.0. the fabric dyes to a dark blue and [(2.2.6.6-tetramethyl-4- at 4.5 to a medium blue- 1 piperidinyl)sulfamoyl]fluorene-9,9-dipropionic acid.

dimethyl ester. Compound X1; N,N'-[6-([2.2.6,6-

EXAMPLE 7 tetramethyl-4-piperidyl]amino)-s-triazine-2.4-

This example illustrates the use of a reduced amount y l y fl Compound yof Compound VI in preparing filaments of a different [i y 'pP y i d hl COpO]yeSte|- Compound XIV; and 2.4-dimethoxy-6-[(1.2.2.6.6-

A dry ethylene terephthalate polyester having a rela- PcntamethylA-piperidyl)aminol's'triazinei cm'flpound tive viscosity of 25.0 and containing about mole per- XV- The mo ifi p ly r fil m n f rics nd cent 2.2-dimethyl-l,3-propanedio1 units is placed in a dyed fabrics are prepared using the procedures depolymer test tube with 2.1 grams ofCompound VLThe 7 scribed n a ple Th polymers used for 1 tube is provided with a rubber stopper carrying a stirrer blending with the above compounds are P y y and a glass tube. The contents are purged with nitrogen terephthalute (Z T). polyethylene terephthalate eonand evacuated; the process being repeated 4 times. The mining copvlymerized adipflte Units corresponding 10 contents are then heated until melted at 255C. under mole Pfircem adipic d (2GT/6) and i1 P y nitrogen, about minutes, stirred under nitrogen at as 9H6 terephthfllflte P p using mOle p of 255C. for 0.5 hour and then stirred for 2 hours at y B'P p 255C. at a pressure of less than 1 torr. The polymer is Conditions and results are Show" Tables then put under nitrogen and cooled. The polymer is cut to flake and the nitrogen content determined. The pol- I ymer is calculated to contain 0.077: basic nitrogen. The m ZZ; Tlhlcs HM polymer has a relative viscosity of 15.0.

The polymer is then spun into a S-filament yarn at a POLYMER spinning block temperature of 250C. and a spinneret F Y O No. Com- Temp. C. Composition Viscosity temperature of 255 C. and wound to a package. The pmmd spun yarn is drawn over a hot pin at 85C. The draw 2 ratio is 3.0 and the feed roll speed is 161.7 yards (15.3 3 meters) per minute. Two of the drawn yarns are plied. [0 viii 15% 20176 19.5 3 a '2 ii XI 255 ZGT/fi 19.5 The plied yirn his a denier oi 6. i tepticity of I: X 255 2on6 18.8 grams per denier and an elongation of 74 /r. The plied 13 IX 383 -176 [M4 yarn is knit to a fabric and the fabric scoured and dyed 4U 1X 355 2G/DIVUCIT 15 x 283 2(iT m4 at pH 3.0 and 4.5 using the procedure described in Ex- [X 383 335 ample 1. At pH 3.0. the fabric dyes to a dark blue and r .u. at 4.5 to a medium blue. 9 xv 255 ZG-M 3m 20A ix 2x3 EXAMPLES 8-19 20B IX 2x3 These examples illustrate the use of the following in f -l'l)\lfli\ l l) lilll'upl'llllillilh: monomer used.

TABLE 11 Basic SolidPhiise Ex. Nitrogen Polynicri2a- Polymer. Spinning Temps No, Content. tion. Hours Rel. Vise. Block Spiiincret x 0,13 113 14.0 25b 9 mix 113 26.3 250 254 10 0.08 113 31.0 251 252 11 um 113 275 25s 261 12 0.08 so (11.7 280 2x5 13 (in n 17.3 260 265 I4 our 0 18.7 2:: 205 15 0.08 41* ms 2x0 282 in 0.14 mi 2x3 3x7 17 0.1-: (1 21m 260 260 ii 0.12 ii: 24.5 2h5 2&4 19 0.02 mu siis 2x0 2240 20A 0.224 0 3m 2x5 208 0,12 432 340* 294 2% "(1i Iculaitcd tained at 0.05 torr at 283C. for l hour. The polymer is then cooled under nitrogen. cut to flake. the nitrogen content determined and solid-phase polymerized.

Filament and fabric preparation and dyeings are carried out using the procedures described in Example 5. Conditions and results are shown in Tables l-I\/.

I claim:

1. Acid-dyeable textile fibers or filaments of a linear glycobtcrephthalate copolyester with a minor proportion. sufficient to provide at least 0.02 weight percent nitrogen, of a 2.2.6.6-tetramethylpiperidine compound having substituents at the l and/or 4 positions on the tetramethylpiperidine ring which Comprises a total of two ester-forming groups. each group being attached directly to the tetramethylpiperidine ring or attached to a tetramethylpiperidine ring substituent.

2. Fibers or filaments as defined in claim I wherein the copolyester comprises at least 85 mole percent eth- TABLE Ill Ex. Draw Hot Pin Properties of the Z-Plied Yarn No. Ratio" Tc|n 1.. C. Denier Tenaeit gpd. Elongation n K 4.5 83 b4 2.2 4l 9 3.5 N3 511 2.3 49 10 3.5 83 40 ll 34 l l 4.5 8.1 So 2.) 23 II 3.5 83 SI 2.7 46 l3 1.5 85 89 l .3 7-4 l4 3.0 85 I18 1.2 54 I5 3.0 85 12. 1.3 76 lh* 1,5 85 38 L X7 17 .0 X 77 L5 9b 18 4.0 85 I ll 42 I) 4.0 85 )2 2.) l2 20A .0 85 204 0.6 37 208 3.0 R5 '98 L6 65 *Feed roll speed is ll|.7 yards t 15.3 meters) per minute for Fumtplcs #20]! TABLE IV lax. Shade From Dyeing 70 No. pH 3.0 pH 4.5 U

H Dark Dark Dark Dark 10 Dark Dark l I Dark Dark 11 Medium Light I3 Dark Dark l-l Light Light l5 Medium lo Dark Medium l7 Light IN Light Light I) Light 3 20A Medium 208 Medium Medium *Skein dyed EXAMPLE 20 s This example illustrates the use of di( 2- hydroxyethyl) terephthalate and two different concentrations of Compound lX in preparing acid-dyeable copolyester filaments. Run A lnto a 500-milliliter, 3-necked, round-bottomed flask is placed 100 grams of di(Z-hydroxyethyl) terephthalate. 3.8 grams of Compound IX. 4 milliliters of Sb O in ethylene glycol (taken from a stock solution containing 1.4 grams of Sb. ,O;, in 100 milliliters of ethylene glycol). The round-bottomed flask is provided with a stirrer and an inlet-outlet tube. The contents are purged with nitrogen and evacuated; the process being repeated 4 times. The contents are heated under nitrogen in a salt bath at 283C. until melted. The pressure is then reduced to L0 torr over a period of IS to 20 minutes. The contents are maintained at not greater than 10 torr. and at 283C. for 1 hour. The polymer is then cooled under nitrogen and cut to flake and the nitrogen content determined.

Run B In a 2-liter. 3-necked. round-bottomed flask is placed 500 grams of di-(2-hydroxyethyl) terephthalate, ll.3 grams of 5-[(2.2,6.6-tetramethyI-4-piperidinyl)sulfamoyll-isophthalic acid and 20 milliliters of Sb O in ethylene glycol (taken from a stock solution containing l.4 grams ofSb O; in I00 milliliters of ethylene glycol). The flask is provided with a stirrer and an inlet-outlet tube. The contents are purged with nitrogen and evacuated; the process being repeated 4 times. The contents are heated under nitrogen in a salt bath at 283C. for 0.5 hour. The pressure is then reduced to l.() torr over a period of 15 to 20 minutes. The contents are mainylene terephthalate units.

3. Fibers or filaments as defined in claim 2 wherein the copolyester comprises 2 to 10 weight percent ethylene adipate units.

4. Fibers or filaments as defined in claim 1 wherein the copolyester comprises an amount of tetramethylpiperidine compound which provides 0.02 to 0.25 weight percent nitrogen, based on the weight of copolyester.

5. Fibers or filaments as defined in claim I wherein the tetramethylpiperidine compound has substituents at the l and 4 positions of the tetramethylpiperidine ring and each substituent comprises an ester-forming group.

6. Fibers or filaments as defined in claim I wherein the tetramethylpiperidine compound is a glycol.

7. Fibers or filaments as defined in claim 1 wherein the tetramethylpiperidine compound is a dicarboxylic acid.

8. Fibers or filaments as defined in claim I wherein the tetramethylpiperidine compound is a hydroxy acid.

9. Fibers or filaments as defined in claim 1 wherein the tetramethylpiperidine compound is an s-triazine derivative containing two ester-forming groups.

10. Fibers or filaments as defined in claim I wherein the tetramethylpiperidine compound is l-( 2- hydroxyethyl )-2,2.6,6-tetramethyl-4- hydroxypiperidine.

l l. Fibers or filaments as defined in claim 1 wherein the tetramethylpiperidine compound is I-(Z-hydroxy- Z-methylethyl)-2.2.6.(i-tetramethyl-4- hydroxypiperidine.

1S. Fibers or filaments as defined in claim 1 wherein the tetramethylpiperidine compound is [(216.6- tetramethyl-4-piperidinyl )sulfamoyl ]fluorene-9,9- dipropioniute.

l6. Fibers 0r filaments as defined in claim I wherein the tetrumethylpiperidine compound is 2,2'-[4,6- his(2 2,6,fi-tetramethyll-piperidyl]z1min0)-s-triazine- 2-ylimin01-diethan0l. 

1. ACID-DYEABLE TEXTILE FIBERS OR FILAMENTS OF ALINEAR GLYCOLTEREPHTHALATE COPOLYESTER WITH A MINOR PROPORTION, SUFFICIENT TO PROVIDE AT LEAST 0.02 WEIGHT PERCENT NITROGEN, OF 2,2,6,6TETRAMETHYLPIPERIDINE COMPOUND HAVING SUBSTITUENTS AT THE 1 AND/OR 4 POSITIONS ON THE TETRAMETHYLPIPERIDINE RING WHICH COMPRISES A TOTAL OF TWO ESTER-FORMING GROUPS, EACH GROUP BEING ATTACHED DIRECTLY TO THE TETRAMETHYLPIPERIDINE RING OR ATTACHED TO A TETRAMETHYLPIPERIDINE RING SUBSTITUENT.
 2. Fibers or filaments as defined in claim 1 wherein the copolyester comprises at least 85 mole percent ethylene terephthalate units.
 3. Fibers or filaments as defined in claim 2 wherein the copolyester comprises 2 to 10 weight percent ethylene adipate units.
 4. Fibers or filaments as defined in claim 1 wherein the copolyester comprises an amount of tetramethylpiperidine compound which provides 0.02 to 0.25 weight percent nitrogen, based on the weight of copolyester.
 5. Fibers or filaments as defined in claim 1 wherein the tetramethylpiperidine compound has substituents at the 1 and 4 positions of the tetramethylpiperidine ring and each substituent comprises an ester-forming group.
 6. Fibers or filaments as defined in claim 1 wherein the tetramethylpiperidine compound is a glycol.
 7. Fibers or filaments as defined in claim 1 wherein the tetramethylpiperidine compound is a dicarboxylic acid.
 8. Fibers or filaments as defined in claim 1 wherein the tetramethylpiperidine compound is a hydroxy acid.
 9. Fibers or filaments as defined in claim 1 wherein the tetramethylpiperidine compound is an s-triazine derivative containing two ester-forming groups.
 10. Fibers or filaments as defined in claim 1 wherein the tetramethylpiperidine compound is 1-(2-hydroxyethyl)-2,2,6,6-tetramethyl-4-hydroxypiperidine.
 11. Fibers or filaments as defined in claim 1 wherein the tetramethylpiperidine compound is 1-(2-hydroxy-2-methylethyl)-2, 2,6,6-tetramethyl-4-hydroxypiperidine.
 12. Fibers or filaments as defined in claim 1 wherein the tetramethylpiperidine compound is 5-((2,2,6,6-tetramethyl-4-piperidinyl)sulfamoyl)isophthalate.
 13. Fibers or filaments as defined in claim 1 wherein the tetramethylpiperidine compound is 5-((2,2,6,6-tetramethyl-4-piperidinyl)sulfamoyl)isophthalic acid.
 14. Fibers or filaments as defined in claim 1 wherein the tetramethylpiperidine compound is 5-((1,2,2,6,6-pentamethyl-4-piperidinyl)sulfamoyl)isophthalate.
 15. Fibers or filaments as defined in claim 1 wherein the tetramethylpiperidine compound is ((2,2,6,6-tetramethyl-4-piperidinyl)sulfamoyl)fluorene-9,9-dipropioniate.
 16. Fibers or filaments as defined in claim 1 wherein the tetramethylpiperidine compound is 2,2''-(4,6-bis(2,2,6,6-tetramethyl-4-piperidyl)amino)-s-triazine-2-ylimino) -diethanol. 